It’s been 14 months since the popular Lake Union Park Bridge for pedestrians was closed due to a structural problem. A fix is still months away.
With public projects, things get done when things get done.
Which is why those working at Seattle’s Lake Union Park will now be on Year Two of being asked: When is that popular pedestrian bridge going to get fixed?
Maybe by this summer, maybe a little longer.
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The bridge has already been closed for 14 months, and the closure could total 20 to 24 months.
There are large cyclone fences at both entrances to the bridge, structures that got taller as kids kept climbing them so in the summer they could jump into the lake.
“We get asked about it constantly, people voicing their displeasure. We tend to be the targets. They think we’re responsible,” says Jason Young, senior manager of security and facilities at the Museum of History & Industry, better known as MOHAI, which is located at the park, on the lake’s southern shore.
Young refers people with bridge questions to Seattle Parks and Recreation. This is a park, after all.
And at a public agency, would you want to be the decision-maker who rushed a bridge fix and then something went wrong?
The 108-foot-long bridge certainly looks sturdy enough, with nice, big concrete abutments at each end on which sits the bridge. Plenty of iron, too.
But better be safe than sorry, and do a geotechnical assessment after regular inspection of the bridge showed movement on the east abutment. The ground had settled some 6 inches.
The abutment had moved laterally, which meant a “loss of camber,” which is the amount of arching on a bridge to counter a heavy load. Without camber, the bridge would sag under a heavy load.
“You wouldn’t notice it by the naked eye,” says Toby Ressler, a project manager with Seattle Parks.
But, he says, if there was enough compression on the bridge, “It could snap.”
The bridge, built before the park officially opened in 2010, had been widely used to cross a finger of the southwestern part of the lake.
It was a shortcut for visitors parking at the west side of the lake to go to the museum and to the Center for Wooden Boats.
“It makes a difference for older people who have to walk around,” says Mike Luis, executive director of the boat group, which also keeps getting asked about the bridge.
But things happen when you build on fill.
As the geotechnical report commissioned by the city says, among the stuff found in the soil was sawdust.
A historical photo from around 1885 shows a sawmill, as well as homes of workmen who earned their living cutting lumber. One of prime investors in the mill was David Denny, after whom Denny Way is named.
The soils at the park, says Ressler “are all fill … a liquefaction zone.”
That means current structures sit on steel piles that go down 100 feet. Really, in an earthquake, a liquefaction zone is not where you want to be.
The most likely bridge fix, says Ressler, is to dig out the existing fill around that east abutment and replace it with what are called geofoam blocks, a lightweight fill material that causes much less settlement.
So far, he says, the project, including consultant fees, has cost $150,000. That includes small repairs to sidewalks in the park which are also cracking because of settlement. Then there is the pond in the park, which has settled 3 inches at one end.
Seattleites are quite familiar with shifting soils.
The city lists a budget of $350,000 to fix the bridge.
Ressler says the work will be done sometime this year.
“I don’t think it’s taken long at all,” he says. “We really wanted to make sure it’s the right fix for the bridge.”
By the way, if you go Google Maps and type in “Lake Union Park,” the bridge will not be labeled as the Lake Union Park Bridge, but “Safeco Bridge.”
Seattle Parks says it has no idea why Google gave it that name, or if somehow Safeco bought the naming rights.
But, you know, that’s about enough questions about the bridge for now, don’t you think?